IV.
ON THE MECHANICAL CONCEPTION OF NATURE.
Introduction, p. [634].
Results of the three foregoing essays: denial of a phyletic vital force, [634]. Application of these results to inductive conclusions with reference to the organic world in general, [636]. The assumption of such a force is opposed to the fundamental laws of natural science, [637]. The “vital force” of the older natural philosopher, [640]. Why was the latter abandoned? Commencement of a mechanical theory of life, [642].
I.
Are the Principles of the Selection Theory Mechanical? p. [645].
Refutation of Von Hartmann’s views, [645]. Variability, [646]. The assumption of unlimited variability no postulate of the selection theory, [647]. The acknowledgment of a fixed and directed variability does not necessitate the assumption of a phyletic vital force, [647]. Heredity, [657]. Useful modifications do not occur only singly, [657]. New characters appearing singly may also acquire predominance, [659]. A mechanical theory of heredity is as yet wanting, [665]. Haeckel’s “Perigenesis of the Plastidule,” [667]. Correlation, [670]. The “specific type” depends upon the physiological equilibrium of the parts of the organism, [671]. The theoretical principles of the doctrine of selection are thus mechanical, [675]. Importance of the physical constitution of the organism in determining the quality of variations, [676]. All individual variability depends upon unequal external influences, [677]. Deduction of the limitability of variation, [682]. Deduction of local forms, [686]. Parallelism between the ontogenetic and the phyletic vital force, [687]. The two are inseparable, [690].
II.
Mechanism and Teleology, p. [694].